Saturday, September 09, 2006

Know that we Jews have three kinds of books: the first is the Bible, and we all believe in this with perfect faith; the second is called the Talmud, and it is an explication of the commandments of Torah, for there are 613 commandments in the Torah, and every single one of them is explicated in the Talmud, and we believe in this explication of the commandments; and we have also a third book which is called Midrash, which means "Sermons". This is just as if a bishop were to stand up and make a sermon, and one of his hearers liked it so much that he wrote it down. And as for this book, the Midrash, if anyone wants to believe in it, well and good, but if someone does not believe in it, there is no harm....Moreover, we call the Midrash a book of "Aggadah", which means "razionamiento", that is to say, merely things that a man relates to his fellow.

This is from the Vikuah of Nahmanides, an account of a disputation in Barcelona between the great rabbi and Fray Paul before King James I of Aragon. Nahmanides, also known as Moses ben Nahman or Ramban (not to be confused with Rambam, who is Maimonides), was the last great figure in the waning years of what has been called the Spanish Golden Age for the Jews. In Spain, unlike elsewhere, the perpetual conflict between Christian and Muslim had forced both sides to make alliance with Jews. The result on both sides was a flowering of Jewish culture thatwas unrivalled until the Haskallah, or Jewish Enlightenment, and perhaps not even then. It was not a perfect time for Jews. While the Christian-Jewish alliance in Christian Spain (which, of course, was becoming a larger and larger part of Spain through much of the late Middle Ages) gave Jews more room to flourish on their own terms than ever before, it was nonetheless precarious; Spanish monarchs were perpetually under external and internal pressure to enforce the anti-Jewish laws that were still technically on the books. While Jews could and did do very well for themselves, there was always a sort of implicit qualification: they rose to power, wealth, and influence in the way foreigners with needed skills may rise to it.

As Maccoby notes in his discussion of the Barcelona Disputation (which took place in 1263), the fact that the disputation took place at all was a sign of just how far the Golden Age had waned. Nonetheless it is a remarkable tribute to Spain at the time that this Disputation, while not perfectly fair (it was, after all, Catholic Spain, and Nahmanides had to watch his step in a way the Catholics did not), was nonetheless very close to it, and we find in Nahmanides' Vikuah one of the greatest and most courageous Jewish minds of the Middle Ages meeting Christianity head on and not backing down. One of the features of the Disputation is that, while the playing field was Christian, the Jews had an advantage in the debate. At this period in time, the Dominicans were pioneering a new way of seeking Jewish conversion. Instead of preaching at them how stiffnecked they were (which at the time was a surprisingly common approach to persuading Jews to follow Christ), they made an attempt to speak to Jews in their own terms, appealing to the Talmud and to various books of Midrash to argue (abstracting entirely from the question of whether Jesus was the Messiah) that it was possible to establish a Jewish defense of the claims (1) that Messiah had come; (2) that Messiah had to die; and (3) that Messiah had to be divine. While politically the home court advantage always went to the Catholics, this new missionary tactic had the consequence that the terms of the debate favored the Jews, at least in principle. Jewish converts like the Fray Paul Christiani mentioned in the passage above used their pre-conversion study as a jumping-off point for disputing with the Jews.

Of course, the Jews themselves were not inclined to like this much more than any other sort of dispute. They wanted to be left alone; and, since they could not disobey the magistrates who summoned them to these debates, they generally sought as much as they could to evade any direct conflict head on. However, in this one case we have a Jew who felt he could speak more plainly arguing, in front of a monarch who, despite being definitely Catholic, had considerable sympathies with the Jews, many of who he depended on for running his kingdom, against Christian opponents who, while intelligent and learned in their own right, were no match for his genius. It's a fascinating result, particularly since we get Nahmanides's own perspective on the Disputation, and a very firm insistence on the claim that Judaism is a more rational religion than Christianity. We also get interesting cases in which Nahmanides struggles to convey to Christians some insight into aspects of Jewish life -- the primal importance of law, the secondary importance of doctrine, the concepts of midrash and haggadah, and so forth -- that were very foreign to Christian minds. To do so he has to simplify, of course (as he does in the above passage), but, being Nahmanides, he is still able to convey the basic point.

Why is it that people will actually criticize others for being reasonable? That is precisely what Jason Rosenhouse did in a recent post on people who are religious and 'moderate', i.e., don't close their eyes to scientific progress. That's a broad, vague category; it would be utterly silly to think that there is any one criticism that can be leveled against the category as a whole, but Rosenhouse comes very close to trying to do this. He argues:

The problem is that theological moderation is even harder to defend than fundamentalism.

A lot of people say a lot of things in the dispute between science and religion. There are arguments and counter arguments ad nauseum on both sides. Many of these arguments are fascinating and reward careful study, which, indeed, is why I spend so much time on them at this blog.

But when you strip away all the logic chopping and the careful parsing of Genesis you're left with a simple truth that no theologian has yet been able to make go away. It is this: Evolution by natural selection just isn't what you expect from a world created by an act of God's will for the amusement of humans.

Of course, if we take enough trouble to do our homework, we can find pretty easily that 'the world was created by an act of God's will for the amusement of humans' has been regarded as an absurd oversimplification for hundreds of years. Indeed, it has been commonly denied; and it takes no great literary competence to see that reading this into Genesis requires very selective reading.

And that is what precisely this sort of thing is: eisegesis rather than exegesis. Rosenhouse and others like him make the mistake of assuming that fundamentalists are reading more rationally than those who take explicit pains to read more carefully. On the basis of what do they make this surprising assumption? In and of itself it should give them pause enough to reflect on whether they might be on the verge of sophism; but, since they don't pause at all, but rush headlong into the conclusion without any questioning of their assumptions, the sophism moves right along as if it were a good piece of reasoning.

Further, it is clear that Rosenhouse is confusing this issue with other issues. For instance, he argues:

You can explain it after the fact, of course. You can say that evolution is God's means of creation, or you can transform Genesis from an unambiguous sequence of historical events into a parable meant to teach theological truths, or you can gush that God put in place a system of natural laws so wonderful that it was sufficient to bring about his creative ends, or you can argue that somehow humanity or something like it was the inevitable result of evolution. The fact remains that God chose a mechanism for creation that got hung up at the bacteria stage for three billlion years, and then needed an assist from several mass extinctions after clearing that hump. This, when he could simply have snapped his fingers and brought his world into being.

But there is no 'explaining it after the fact' here. Rather, what's going on is exactly what one would expect of a reasonable person: if you want to know how the world works, you go to the world and look at how it works. And there's nothing about believing that the world is created by God that would change this. Rosenhouse says that God "could simply have snappend his fingers and brought his world in being". Perhaps so. But if you want to know what world was brought into being, snapped fingers or no, you will, if you are a reasonable person, look to see what world was brought into being. And the world that we find if we look into this matter is a world consisting of a vast number of galaxies, each with a vast number of stars, around one of which we find ourselves on a planet. Rosenhouse summarizes the history of the planet as "a mechanism for creation that got hung up at the bacteria stage for three billion years, and then needed an assist from several mass extinctions after clearing that hump." How he or anyone else would know that it got 'hung up' at one stage and 'needed an assist' at another he doesn't say; and he apparently forgets that if God can "snap his fingers" and make the whole universe exist, there's no reason to assume he couldn't have three billion years of bacteria alone and a bunch of mass extinctions on one tiny planet in a vast array of stars. There's no room here for 'getting hung up' or 'needing an assist'; it's either rhetoric backed up by no reasoning, or a rather serious category mistake.

And, again, if you consider yourself to have reason to believe that God created the universe, and you want to know about this universe that God created, as many of us do, you look and see. If the heavens are telling the glory of God, you don't close yourself up in a room and speculate groundlessly about what sort of universe God would make; you inquire into the universe He did make, you raise your head to the heavens and see.

Rosenhouse then goes on to say:

And it's not just evolution. The Catholic Church used to think it was a very big deal to claim that the Earth was not the center of the universe. They were right to think it a big deal. If the Earth is the point of it all then it is rather hard to explain why God also created billions of other galaxies with stars orbited by lifeless worlds. Since theological reasoning is constrained only by the imagination of the reasoner, it is possible to conjure up explanations for this fact. And who knows? Maybe you're one of those people who can actually talk yourself into believing those explanations.

Yet if we were actually to look at the real historical evidence, we would find that what was more often thought a big deal was the claim that the sun was the immovable center of the universe; in the Galileo controversy, for instance, this is explicitly treated as the more serious problem. People did, of course, believe that the earth was at the center of the universe, and did think it a big deal when other people began to hold that it was not. But on what evidence shall we say that they believed this because they thought that "the Earth is the point of it all"? One wonders; because in medieval cosmology it is usually clear that the Earth is not the point of it all. If we are going to talk about importance, the reason they thought the earth was at the center of the universe was that it was the least important body in the heavens. All the other bodies in the heavens moved in circles, and moving in circles was, in Aristotelian and Platonic eyes alike, the most perfect sort of motion. A body that did not move in circles (like the stationary Earth) was thereby shown to be an imperfect sort of body. Further, the Earth did not even have the distinction of bearing the most important people in the universe. Human beings, far from being considered the most intelligent creatures in the guide, were considered the least intelligent: of all the intelligences in all the universe, we were the least impressive, because we were on the edge -- we were just intelligent enough to be considered genuine intelligences (we could think in universal terms and act morally) but were still rather dimwitted in comparison with other intelligences the medievals recognized. Far more impressive were the intelligences associated with the heavenly bodies; far more impressive than they were the intelligences of the empyrean. On such a view of the universe, what sense could be made of the claim that "The Earth is the point of it all"? So if Rosenhouse has an argument here, we need more information -- the evidence on which he is basing this claim -- in order to know what it is.

I've tried not to be completely harsh in this post. The sort of argument Rosenhouse is making is one of my pet peeves, because it seems to me to be a very bad strategy all around: fighting pseudoscience is not a sufficient justification for propagating pseudohistory; arguing against irrationality is not a good reason for failing to provide good reasoning oneself. It is simply unwise to attack fundamentalists for not making proper and reasonable distinctions and then go on in the next breath to avoid making proper and reasonable distinctions oneself. It is unreasonable to criticize reasonable people for being reasonable about the world. And a lot of this argument is just argument of the "I know better than you do, from a superficial reading, what the text you've studied all your life says" kind of argument. And as I've pointed out before in a very different context, this is usually absurd through and through. Let's move beyond this to a reasonable approach.

Thursday, September 07, 2006

While doing a bit of reading on the subject of eighteenth century theories of taste, I came upon an amusing incident in the history of scholarship that I thought I would pass on. For some time it had been known that Frances Reynolds, the sister of Sir Joshua Reynolds and a correspondent of the great Samuel Johnson, had printed as a pamphlet in 250 copies, an essay on taste. Very little was known of it, however. It seemed to be quoted by James Northcote in his early nineteenth-century Life of Sir Joshua Reynolds, but none of the quotations ever seemed very helpful; and people began to suspect that either Northcote was mistaken about the source (i.e., mistakenly thought the text he was quoting was by Reynolds) or he was quoting an early draft that may have been very different from the one actually printed. (It turned out they were right.)

In the meantime, scholars were trying to hunt down another, even more mysterious work of Reynolds's, which she had sent to Johnson for comments. Johnson had responded (8 April 1782) kindly but critically. The letter everyone had access to was that printed by Croker and later by Hill:

Your work is full of very penetrating meditation, and very forcible sentiment. I read it with a full perception of the sublime, with wonder and terrour, but I cannot think of any profit from it; it seems not born to be popular.

Your system of the mental fabric is exceedingly obscure, and without more attention than will be willingly bestowed, is unintelligible. The plans of Burnaby will be more easily understood, and are often charming. I was delighted with the different beauty of different ages.

I would make it produce something if I could but I have indeed no hope. If a Bookseller would buy it at all, as it must be published without a name, he would give nothing for it worth your acceptance.

High and low scholars looked for this otherwise unknown novel or short story about the plans of Burnaby. It never came to light.

Which is not surprising, as there was no Burnaby. Johnson's actual letter never said anything about the plans of Burnaby; it was a faulty transcription. The actual letter, instead of 'The plans of Burnaby' had 'The Ideas of Beauty'. The Burnaby story was really the essay on taste!

In any case, having more information in hand it was possible to identify the work. You can read it, and, in the introduction, James Clifford's account of the history of the work, at Project Gutenberg. It strikes me as a nice little parable for all scholars everywhere. Every discipline has its own versions of the plans of Burnaby, whether on a small scale or a grand one -- that stunning little piece of evidence that sends you on a wild goose chase because it is, unbeknownst to you, all wrong. Beware the plans of Burnaby!

Wednesday, September 06, 2006

I've run across arguments like this quite often, but I've never understood the reasoning:

I think I can understand the difference between having whiteness according to its full power and having whiteness according to something less than its full power, because, I take it, it is the difference between being less than perfectly white and being perfectly white. By contrast, there does not seem to be a difference between being perfectly existent and being less than perfectly existent. Existence is an on/off property: either you're there or you're not. Because existence is on/off, it would seem, either you have it according to its full power or you don't have it at all.

This particular version of the argument is directed at Aquinas; I'm setting aside the question of whether 'existence' as we usually understand it is an adequate translation of Aquinas's esse (I don't think it is, outside of certain narrow contexts; the notions overlap, of course, but there are a number of reasons to regard 'existence' as a term that fails to coincide very well with esse in meaning). Instead I want to point out that arguments like this seem to make an unwarranted leap. Suppose that X is an 'on/off' property; you either have it or you don't. It doesn't follow from this that you can't have degrees or gradations of X when it's 'on'. Why would it? The mere fact of there being no tertium quid between 'on' and 'off' tells us nothing about the nature of 'on'.

What people appear to be doing in these arguments is confusing 'degrees of X' with 'degrees between X and non-X'. The two are not the same, however similar the answers to questions about them may be in particular contexts. The first is a scale of X; the second is a scale between X and non-X, and these are two different scales. To have the former, you just need X to admit of intension and remission -- X's need to have some feature or characteristic that can be described by 'more' or 'less' in comparison with other X's. To have the latter, you need to have a characteristic or feature that X and non-X share in different intensities and or strengths. For the former, X can be a very precise sort of thing -- sharp boundaries between X and non-X -- without causing problems for the scale. For the latter, the line between X and non-X has to be fuzzy, vague, blurred. However similar they may seem, they really are extremely different.

So, even if existence cannot admit of degrees of 'fullness of existence' or 'perfection of existence qua existence' or what have you, the mere fact that things either exist or don't is not a good reason for thinking so. So it is with other things. To have degrees of truth, for instance, you don't have to admit that there are degrees between truth and falsity (likewise with degrees of falsity). Being committed to the claim that there are degrees of beauty is not enough to commit you to the claim that there are degrees between the beautiful and the non-beautiful. Commitment to the claim that there are degrees of goodness isn't a commitment to the claim that there are degrees between being good and not being good.

I have no wit, no words, no tears;My heart within me like a stoneIs numbed too much for hopes or fears.Look right, look left, I dwell alone;I lift mine eyes, but dimmed with griefNo everlasting hills I see;My life is in the falling leaf:O Jesus, quicken me.

My life is like a faded leaf,My harvest dwindled to a husk:Truly my life is void and briefAnd tedious in the barren dusk;My life is like a frozen thing,No bud nor greenness can I see:Yet rise it shall--the sap of spring;O Jesus, rise in me.

My life is like a broken bowl,A broken bowl that cannot holdOne drop of water for my soulOr cordial in the searching cold;Cast in the fire the perished thing;Melt and remould it, till it beA royal cup for Him, my King:O Jesus, drink of me.

Sunday, September 03, 2006

In previous posts in this series I've been attempting to provide a rough characterization of basic SETL. In Part I, I noted the basics of SETL, in a rough way. In Part II and Part III, I discussed briefly some special cases and how SETL handles them. In Part IV, I discussed some basics of argument using SETL. Part V looked at some simple arguments for which SETL gives us a better sense of what's going on than ordinary predicate logic does. (There will be a post at the end of the series giving references and supplementary readings.)

In this part I want to look a bit at how one might go about incorporating modality into SETL. The work that has been done to this end is still incomplete, but turns out to be immensely promising.

Propositional vs. Predicate Modality

When we have a modality, like necessity, should we take it as modifying the predicate or as modifying the whole proposition? In language we sometimes seem to do one or the other. For instance, we might say,

It is possible that the new animal is a mammal.

And that seems to be propositional modality. However, we might also say,

The new animal is possibly a mammal.

This makes it look like a predicate modification. One could, perhaps, hold that they are equivalent; but this seems very clearly not to be true. A more abstract example might help. Compare:

Necessarily, no B is nonB.No B is necessarily nonB.

'Necessarily' is clearly doing different work here. In the one, "No B is nonB" is taken as a necessary truth. The second, however, does not imply this. It doesn't rule out the possibility that some B is nonB; the only possibility ruled out is that some B is necessarily nonB. It could be true, for all that we can tell from this sentence alone, that some B is non-necessarily nonB. Very different sorts of modality.

The distinction noted here is often called the de re/de dicto distinction for modality; I'll instead continue to use the terms I've already introduced and call it the distinction between predicate and propositional modality.

Predicate and Propositional Modality in SETL

How would we go about incorporating predicate modality into SETL? It turns out that this is very easy. A proposition with predicate modality is simply a proposition with a modalized predicate. Thus, we can simply add modal functors to our predicates. Then we can simply use our ordinary SETL rules, just adding a few basic modal laws (e.g., if +S+P, we can conclude +S+◊P). Let's put up two axioms:

Axiom 1. If x, then x.Axiom 2. If x, then x◊.

For instance, +S+P implies +s+◊P; +S+P implies +S+P. With these we can handle all the important logical relations that hold for predicate modality.

Propositional modality is a more complicated affair, and to see how we could handle it, we should perhaps take a moment to look at domains again. Every proposition is put forward relative to a domain of discourse; to contradict each other "There are dragons" and "There are no dragons" have to presuppose the same domain (if the domain of one is fictional beast mentioned in Piers Anthony novels and the domain of the other is real animals, for instance, they simply don't conflict). Any logical relation between two propositions, in fact, requires some connection of domains. We could state this by saying that every statement denotes its domain; and what a statement signifies is what it says of that domain. "Dragons are blue" says of the domain of the sentence that it includes blue dragons. When we say a statement is true, we mean that the domain it denotes includes the feature it signifies.

Putting it this way, however, simplifies matters considerably, because some statements, while having a domain, don't have a determinate domain -- or, if you prefer, their domain is a meta-domain, a domain of domains -- and are therefore harder to pin down. As it happens, all propositionally modalized propositions are of this sort. "Possibly at least one S is P" can't be interpreted as saying that at least one P-characterized S is in a particular domain; rather, it has to be interpreted as saying that there is at least one domain that includes at least one P-characterized S. Likewise, "Necessarily at least one S is P" doesn't mean that there is at least one P-characterized S in a particular domain; it means that in every domain there is at least one P-characterized S.

When we recognize this, it turns out to be fairly easy to see that the contradictory of (Every S is P) is not, as one might think, (Some S is not P), but instead, ◊(Some S is not P); and the contradictory of (No S is P) is ◊(Some S is P); which is actually rather similar to what one finds in predicate modality (the universal + necessity is contradicted by the particular + possibility). If we take SETL and add the following axioms, we can handle all propositionally modal propositions using necessity and possibility:

Axiom 3. If x, then xAxiom 4. If x, then ◊x

And, it turns out, we can combine our two types of modality if we recognize that the following two statements are true:

If x, then xIf x◊, then ◊x.

This gives us a truly lovely square of opposition or, perhaps more accurately, square of implication, for modal statements, which I borrow from Englebretsen:

Each arrow indicates an implication or possible inference, and gives us an excellent sense of the strongest and weakest modal claims, and, for stronger claims, what weaker claims they entail. Claims that are both necessary and universal are at the top; claims that are both possible and particular are at the bottom; everything else is somewhere in-between.

Inferences with Modality in SETL

With our square of opposition we have already said something about how one would handle simple inferences in a modal version of SETL. But we need a way to handle mediate inference. Since predicate modalities are just modalized predicates, DDO, or the rule of mediate inference, is sufficient to handle them. But propositional modalities are more slippery here as elsewhere. DDO is not sufficient. We need to add another rule:

If x and y, then (x and y)

All this only gives a quick glimpse of a vast and important extension of basic SETL. In any case, any system that cannot distinguish predicate modality from propositional modality is hampered in its handling of real-life modal inferences; and one of the nice things about modalized SETL is that it can handle this distinction very well.

In the next post I'll give another quick glimpse of yet another interesting extension, precise quantification.

My mention of Bradwardine on kisses in the previous post reminded me of a commentary on the Song of Songs by James Durham (1622-1658), a Scottish Calvinist. Here is what Durham says on the subject of kisses:

Her great wish is, 'Let him kiss me with the kisses of his mouth.' That it's the Bride that speaks, is clear; she begins, not because love ariseth first on her side (for here she begins, as having already closed with him, and therefore she speaks to him, as one who knows his worth, and longs for the out-lettings of his love) but because such expressions of Christ's love, as are to be found in this Song, whereby his complacency is vented and manifested toward us, doth first presuppose the working of his love in us, and our exercising of it on him, and then his delighting (that is, is expressing his delight) in us: for although the man first suit the wife (and so Christ first sueth for his bride) yet when persons are married, it's most suitable, that the wife should very pressingly long for, and express desire after the husband, even as the Bride doth here after Christ's kisses, and the expressions of his love. Of this order of Christ's love, see Chapter 8 verse 10.

In the words consider, 1. What she desires, and that is, the 'kisses of his mouth.' 2. How she points Christ forth, by this significant demonstrative, 'Him.' 3. Her abrupt manner of breaking out with this her desire, as one that had been dwelling on the thoughts of Christ, and feeding on his excellencey; and therefore now she breaks out, 'let him kiss me,' &c. as if her heart were at her mouth, or would leap out of her mouth, to meet with his.

First, by 'kisses', we understand most lovely, friendly, familiar and sensible manifestations of his love; kisses of the mouth are so amongst friends, so it was betwixt Jonathan and David, and so it is especially betwixt husband and wife.

Next, there are several delightsome circumstances, the heighten the Bride's this esteem of this, the so much desired expression of his love. The first is implied, in the person who is to kiss, it's 'him, let him kiss', He who is the most excellent and singular person in the world,. The second is hinted at in the party whom he is to kiss, it's 'me, let him kiss me,' a contemptible despicable creature; for so she was in herself, as appears from verse 5,6. Yet this is the person, this love is to be vented on. 3. Wherewith is he to kiss? It's with the 'kisses of his mouth;' which we conceive is not only added as an Hebraism, like that expression, 'the words of his mouth,' and such like phrases, but also to affect her self, by expressing fully what she breathed after, to wit, kisses, or love, which are is a more lovely to her, that they come from his mouth, as having a sweetness in it, (Chap. 5:16.) above any thing in the world. That Christ's love hath such a sweetness in it, the reason subjoined will clear, 'for thy love is,' &c. That which is here kisses, is immediately denominated Loves; it is his love that she prized, and whereof kisses were but evidences.

They are 'kisses' in the plural number, partly to shew how many ways Christ hath to manifest his love, partly to shew the continuance and frequency of these manifestations, which she would be at: And the thing which she here desires, is not love simply, but the sense of love; for she questions not his love, but desired to have a sensible expressions of it, and therefore compares it not only to looks, that she might see him, but to kisses; which is also clear from the reason annexed, while she compares his love to wine.

Durham goes on, of course, to discuss comely cheeks, lovesickness, and breasts like young roes in the same sober allegroical vein.

ADDED LATER:

This is only loosely related, but I remembered that Giles of Rome uses kisses to describe the missions of the Trinity in his commentary on the Song of Songs. His claim is that just as in a kiss the corporeal spirit (breath) proceeds from the kisser through the mouth, so the Holy Spirit proceeds from the Father through the Son. So the Father is the osculans (kisser), the Son is the os (the thing one kisses with, namely, the mouth or, more broadly, the face), and the Spirit is the osculum (kiss). That's certainly not one of the analogies you usually hear.

* The Philosophy of Kissing at "Per Caritatem" is must-read for those who like jokes about philosophers. It all does remind me, though, of a serious Scholastic philosophy of kissing. In one of his works (a commentary on the Song of Songs, I think), Thomas Bradwardine tells us, in his serious scholastic way, that every genuine kiss has three parts: a pressing of lips, a mingling of breath, and a union of souls. And, of course, since we're talking about the Song of Songs, he makes some theological point out of this that I have long since forgotten.

I have several posts coming down the pipeline, but I don't know how quickly I'll get them up; I accidentally cut my finger Friday, and while it's not a horrible cut, it's slowing my typing quite a bit. Posting may be light or uneven the next few days, depending on how quickly it heals (so far it is doing well).

ADDED LATER: John Wilkins has a nice acknowledgment of a post I wrote in July on a post he had written about design arguments. I do want to reiterate that my correction doesn't affect the main core of Wilkins's original argument; the only problem with the original post was that the basic argument was obscured by using Aquinas, who had different concerns. I still recommend the original post as a good discussion of basic issues about the concept 'design' as applied to the natural world.

It seems to be a common view that the doctrine of middle knowledge basically holds (1) that counterfactuals of freedom can be true; and (2) that God knows them. This, however, is certainly not right. (1) and (2) are not sufficient for accepting middle knowledge. Strictly speaking, in fact, they don't even seem to be necessary; positions that involve middle knowledge but reject (1) or (2) are not at all attractive for a number of reasons, in part because they seem to make middle knowledge a pointless postulate, but there is nothing inconsistent about such a view.

To understand what middle knowledge is, you have to understand what it is in the middle of. Everyone agrees that God has two kinds of knowledge. The first is sometimes called natural knowledge and sometimes called knowledge by simple intelligence. This is knowledge of things insofar as they are possible; it is called 'natural knowledge' because God is usually said to know these by virtue of the divine nature. The second, sometimes called free knowledge and sometimes called knowledge of vision, is knowledge of things insofar as they are actual. It is called 'free knowledge' because God is usually said to know these by virtue of the divine will, i.e., God knows them by virtue of His choices. There are positions that deny one or the other, but in general everyone accepts these.

To have a middle knowledge position you must hold that this division is incomplete. There is a third, distinct sort of knowledge in between these two: a knowledge of X that is a bit more than knowledge of X as possible and a bit less than a knowledge of X as actual, but is not reducible to any combination of the two. We know in the case of a lot of counterfactuals that it is possible to reduce these to a combination of natural knowledge and free knowledge, because they can be known 'in their causes' -- i.e., given such-and-such actual things, only such-and-such other things are possible. Someone who accepts scientia media holds that there are counterfactuals -- usually counterfactuals of freedom -- that cannot be reduced in this way.

Suppose David does not go to the store. What do we say about this claim:

(D) Had David gone to the store, he would have freely chosen not to buy ice cream.

(We are assuming a freedom that involves alternative possibilities; if this conception of freedom were rejected, there would be no dispute: middle knowledge would be unnecessary, since counterfactuals of freedom would be analyzable in the way any other counterfactual would be.) One way to handle (D) would be to hold that this falls within the jurisdiction, so to speak, of natural knowledge and it alone. If this is so, then usually one would want to say that (D) is neither true nor false; it is merely a possible state among several; or, if it is understood to exclude other possibilities (e.g., Going to the store and choosing to buy ice cream), it is false, because while we can say that David might have bought ice cream had he gone, to say he would have done so leaves out the other things he could have done.

Alternatively one could say that it can be handled by a combination of natural knowledge and free knowledge. Then we can say that (D) is true, but only conditionally so. Most counterfactual statements are only conditionally true (i.e., they are only true ceteris paribus or on the supposition that there is no impediment), so this is not obviously problematic. If I say, "If I had the materials for peanut butter sandwiches, I would be able to make peanut butter sandwiches," this ordinary counterfactual is clearly true on condition that there'd be no other impediment (besides lack of materials) -- e.g., that I wouldn't be suddenly struck with paralysis or something. That is, it is true on supposition that other things are true; it is true, given certain background information.

What the true proponent of middle knowledge argues is that this is not enough. Traditional Molinism, for instance, held that statements like (D) were conditionally true; and they held that the conditions were true but not conditionally so. So, while (D) is only true if certain conditions prevail (namely, a given 'order of nature'), those conditions do prevail. However, they are not known to prevail by virtue of anything that we find in either an account of natural knowledge or an account of free knowledge, or their combination; so, since God knows all truths, we must be missing a type of knowledge, one that is in some ways like natural knowledge (it covers more than what is actual, since it includes counterfactuals) but is in other ways like free knowledge (it admits of contingent truths), but is a distinct type of knowledge falling in between the two. It is open to certain kinds of anti-Molinists to accept that (D) is conditionally true and accept that the conditions are true unconditionally, but to deny the last point, arguing that this can be adequately explained by natural knowledge (e.g., some supercomprehension views) or by free knowledge (e.g., physical premotion) or some combination of the two. The Molinist has to argue that neither natural knowledge nor free knowledge nor their combination can explain this knowledge of this type of counterfactuals.

This, incidentally, is why Molinists cannot avoid facing the grounding objection. The grounding objection is just one specific version of a larger worry about middle knowledge, namely, that it is otiose, and that people who posit it are either proposing an explanation for something that doesn't need an explanation (because there is not really anything to explain), or are proposing a superfluous explanation, i.e., an explanation for something that already is explained by a factor everyone already agrees is there. In other words, the Molinist has to have an answer to the grounding objection because he has to show that there really is a tertium quid between natural knowledge and free knowledge that isn't reducible to some combination of the two. And this is usually where Molinists are weak.

Caveats

For a rough introduction to my philosophy of blogging, including the Code of Amiability I try to follow on this weblog, please read my fifth anniversary post. I consider blogging to be a very informal type of publishing - like putting up thoughts on your door with a note asking for comments. Nothing in this weblog is done rigorously: it's a forum to let my mind be unruly, a place for jottings and first impressions. Because I consider posts here to be 'literary seedings' rather than finished products, nothing here should be taken as if it were anything more than an attempt to rough out some basic thoughts on various issues. Learning to look at any topic philosophically requires, I think, jumping right in, even knowing that you might be making a fool of yourelf; so that's what I do. My primary interest in most topics is the flow and structure of reasoning they involve rather than their actual conclusions, so most of my posts are about that. If, however, you find me making a clear factual error, let me know; blogging is a great way to get rid of misconceptions.